Chemical fixation of CO 2 /CS 2 to access iodoallenyl oxazolidinones and allenyl thiazolidine-thiones.

Constructing heterocyclic compounds by chemical fixation of CO 2 /CS 2 as a C1 building block is a promising approach. An efficient and environmentally friendly synthetic approach has been developed using CO 2 /CS 2 to prepare complicated allenyl heterocycles with high yields and diastereoselectivities in a metal-free manner under mild conditions. NIS promoted CO 2 fixation and the cyclization reaction by exclusive 1,4- syn -addition of 1,3-enynes rather than 1,2-addition or 3,4-addition, while CS 2 participated in unique 1,4- syn -hydrothiolation of 1,3-enynes to afford allenyl heterocycles with different reaction patterns.